The problem of barking dogs has been of continual concern in a variety of different situations. The incessant barking of a dog is undesirable not only because it may be a nuisance to people in the vicinity, but also because it is unhealthy for the barking dog. In a kennel or a clinical veterinary setting, it is desirable to discourage barking, since the barking of one dog is likely to arouse nearby dogs to do the same. In a residential environment, prolonged dog barking is very likely to be an annoyance to neighbors. Throughout the United States, an increasingly large number of communities have enacted "no-bark ordinances" whereby fines or other penalties may be imposed upon the owners of dogs if the owners cannot bring the barking to tolerable levels, durations, or frequencies.
As a result, a variety of techniques and devices have been devised to silence barking dogs. Although formal obedience training presents one possible solution, such training may be expensive, and may not be entirely effective in all dogs. Other approaches include behavioral modification devices which provide, for example, a vibrational response or an electrical shock to the dog in response to its barking. Perhaps the most drastic solution employed for the purposes of silencing barking dogs is the surgical removal of the dog's vocal cords.
The most serious drawback to the aforementioned electrical devices such as shock collars or hand-held electrical prods for discouraging dog barking is that they are, or may at least be so perceived by the general public, inhumane. The extreme measure of surgery to prevent a dog's barking is similarly repugnant. On the other hand, the less drastic measures, such as devices which provide an annoying mechanical vibration to discourage barking, may be quite costly and do not provide an entirely effective means for deterring barking. Moreover, bark-deterring devices are not always capable of effectively monitoring a dog's barking, nor of providing somewhat novel negative-reinforcement or distraction when barking occurs; this is essential to the lasting modification of a dog's behavior.
In order to monitor a dog's barking at all times, it is desirable that the anti-bark device be incorporated into a package which may be worn by the dog, as for example on a dog collar. Known anti-bark devices of this type typically suffer from the limitations that their electronic or mechanical components are housed in a large, inflexible, and cumbersome housing, precluding their use with small dogs. Furthermore, the housings are commonly not waterproof, making the known devices susceptible to damage from the elements. Also, anti-bark devices of the prior art commonly produce only a single negative-reinforcement response to barking. As a result, dogs may become habituated to the stimulus, thus limiting the effectiveness of the device.
Another anti-bark device available in the prior art is one invented by the inventor of the present invention and marketed by Humane Technology, Inc., College Station, Texas, under the trademark "PeaceMaker". The PeaceMaker utilizes CMOS integrated circuits and piezoelectric crystal elements to produce a single high-intensity burst of sound with a decrescendo pattern shortly after detection of a dog's bark. Vocalization discrimination circuitry distinguishes between a dog's barking and extraneous sounds of brief duration. The PeaceMaker is small enough to be fitted onto a dog's collar, and most of the high-frequency sound produced is inaudible to humans. While the PeaceMaker is capable of distinguishing between sounds on the basis of their duration, it does not analyze the frequencies of sounds detected in order to further prevent inadvertent activation. Furthermore, the production of only a single type of sound burst does not alleviate the problems of habituation to the negative reinforcement stimulus.